从powershell正则表达式匹配中提取值

Question

As a part of a buildscript in powershell, I am trying to extract a version number from a string using regular expression. The number is assumed to be in a format xx.yy (eg. 10.6) I need the Integer part (in this example, it would be 10) and the fraction part (example: 6)

I want to have a method that checks that both my patterns exists and thereafter extracts the numbers. (I am very much a novice in powershell, and am trying to avoid using C# functions, but rather powershell itself.)

I tried to do this:

$integralPart="A"
$fractionPart="B"

function GetVersion {
    param([string]$strVersion)
    $integralPattern="^[0-9]+(?=\.)" 
    $fractionalPattern="(?<=\.)[0-9]+$"

    #Check if string consists of an integral and fractional part
    If ($strVersion -match $integralPattern -eq $True -and $strVersion -match $fractionalPattern -eq $True)
    {
        $strVersion -match $integralPattern
        $integralPart = $matches[0]

        $strVersion -match $fractionalPattern
        $fractionalPart = $matches[0]
    } 
    else
    {
        Write-Host "You did not enter a double with an integer and a fractional part (eg. 10.6)"
        Exit
    }
}

GetVersion (Read-Host 'Enter program version')
Write-Host $integralPart
Write-Host $fractionPart

In doing so, I was hoping that $integralPart and $fractionalPart would contain my numbers, at they match the values they should

Can anyone explain how this can be done?

Answer 1

You need to tell PS that the variables are from global scope with $global :

$integralPart="A"
$fractionPart="B"

function GetVersion {
    param([string]$strVersion)
    $integralPattern="^[0-9]+(?=\.)" 
    $fractionalPattern="(?<=\.)[0-9]+$"

    #Check if string consists of an integral and fractional part
    If ($strVersion -match $integralPattern -eq $True -and $strVersion -match $fractionalPattern -eq $True)
    {
        $strVersion -match $integralPattern
        $global:integralPart = $matches[0]   // SEE HERE

        $strVersion -match $fractionalPattern
        $global:fractionPart = $matches[0]   // SEE HERE
    } 
    else
    {
        Write-Host "You did not enter a double with an integer and a fractional part (eg. 10.6)"
        Exit
    }
}

GetVersion "10.6"
Write-Host $integralPart
Write-Host $fractionPart

Output:

True
True
10
6

Also, you have a typo: inside the GetVersion , you have $fractionalPart while the global variable is called $fractionPart .